Js_of_ocaml_webidl__.Union
type ('a, 'b) t
val of_a : 'a Js_of_ocaml.Js.t -> ('a Js_of_ocaml.Js.t, _) t Js_of_ocaml.Js.t
val of_b : 'b Js_of_ocaml.Js.t -> (_, 'b Js_of_ocaml.Js.t) t Js_of_ocaml.Js.t
module Unsafe : sig ... end